Project Summary Chronic obstructive pulmonary disease (COPD) is characterized by airflow limitation, lung injury, and chronic inflammation. Currently it is the fourth leading cause of death in the United States and affects more than 15 million adults. Its prevalence is higher in individuals with household income below poverty level compared to those with higher income. Low income individuals often have unhealthy diets which may have potential adverse respiratory consequences. Further, indoor air quality is also important because Americans spend most of their time indoors and increased particulate matter (PM) exposure in indoor air is associated with worsened COPD morbidity. Because indoor air pollution and diet are both modifiable risk factors it is important to further understand their associations with COPD outcomes. Several studies have reported associations between anti-inflammatory omega (n)-3 and pro-inflammatory n-6 fatty acid dietary intake and worsened COPD outcomes yet other studies have shown no adverse association. No known studies have evaluated the combined effects of fatty acids and indoor PM exposure on COPD morbidity. Potential reasons for the inconsistency in reported outcomes include cross-sectional study design and varying methods of measuring dietary intake and blood levels of fatty acids. Dietary n-3 and n-6 may play a role in the inflammatory state associated with respiratory symptoms and altered lung function in COPD. This project will leverage a local prospective longitudinal cohort study on the role of obesity in susceptibility to air pollution in low income individuals with COPD. Our overall hypothesis is that individuals with diets low in n-3 and/or high in n-6 have worse COPD morbidity including heightened respiratory symptoms, higher inflammation, worse lung function, and will also have higher susceptibility to the adverse impacts of indoor air pollution on respiratory health. A potential mechanism for how fatty acids influence COPD morbidity is through fatty acid derivatives known as specialized pro-resolving mediators (SPM) which work to halt inflammation after resolution of injury. This study will identify how changes in dietary fatty acids are associated with plasma SPM concentrations. The parent study comprehensively assesses indoor air quality, respiratory symptoms, systemic markers of inflammation, and dietary intake as assessed by Food Frequency Questionnaire (FFQ) in 120 former smokers with COPD at baseline, 3, and 6 months. To the existing infrastructure of this study I will analyze omega fatty acid intake measured by the FFQ and collect plasma concentrations of n-3 and n-6, which will reflect short term changes in levels. I will further collect plasma concentrations of SPMs at each time point and assess how they change in association with fatty acid levels. These data are otherwise not being collected and analyzed as part of the parent study. This project is a strong training vehicle for my development as a clinical researcher and will provide a solid platform for a subsequent K23-level project to further evaluate the effects of diet and indoor air pollution exposure in COPD.